jientho 12th Jul 2013, 13:49:
This seems to be a classic case of lack of real-world awareness in software design. What POSSIBLE real-world condition would justify allowing a flight-level-change target of FL000?
There is no such condition. Nobody does that.
Airbus works just same way on "open descend" mode.
It is possible to reduce speed below lowest acceptable when flying manually against FD guidance with both Boeing and Airbus, if autoflight computer guidance is on FLCH or open descend mode, that is not Boeing-specific thing.
That is not the case here, I'm pretty sure of that. Nobody selects 0 feet in alt selector in any situation. Never. That happens only in wannabe pilots' nightmares, never in real world.
Let's wait until we know what really happened. So far we only know that the approach was unstable, "hot and high", and that the control of the plane was not in acceptable level when the plane finally went through glide slope with reducing speed and engines on idle.